A large number of image pickup apparatus capable of shooting a picture of a wide angle of view by using a plurality of cameras have been proposed so far.
For example, there has been proposed an image pickup apparatus in which a plurality of cameras is mounted on a polyhedron frame (see cited patent reference 1, for example).
However, according to this arrangement, since viewpoint centers of the respective cameras are not coincident with each other, parallax (parallax) is produced between the cameras so that a plurality of images cannot be joined with high quality. Also, when it is intended to take a picture of an object near (within the shortest range) the camera, it is unavoidable that the dead angle at which the camera is unable to take a picture is produced.
On the other hand, there has been proposed an image pickup apparatus in which viewpoint centers of a plurality of cameras can be made substantially coincident with each other imaginarily by a pyramidal mirror (see cited patent references 2 and 3, for example)
Cited Patent Reference 1: Official Gazette of Japanese laid-open patent application No. 2001-203924 (FIG. 5)
Cited Patent Reference 2: Official Gazette of Japanese published patent application No. 39-8140 (FIG. 1)
Cited Patent Reference 3: Official Gazette of Japanese laid-open patent application No. 8-307735 (FIG. 1)
In the arrangement using the pyramidal mirror, since the viewpoint centers of a plurality of cameras are optically coincident with each other, those problems of the parallax and the dead angle relative to the object within the shortest range do not arise.
However, since the above-mentioned arrangement needs the pyramidal mirror, problems arise in which the whole of an image pickup apparatus becomes large in size and in which the mirror must be prevented from being cracked or smudged, causing it to be difficult to handle the pyramidal mirror.
Further, since it is not possible to take a picture in the direction along the central axis of the pyramid (in the upper and lower direction in the ordinary location of the pyramidal mirror) due to the structure of the pyramidal mirror, it is difficult to take pictures in all directions.
In order to solve the above-mentioned problem, it is an object of the present invention to provide an image pickup apparatus capable of shooting a picture in a wide range by a plurality of image pickup units which can obtain excellent image quality and which can be miniaturized.